Arduino Board manager

Can someone give me some help please. I am using a Windows 10 P.C. My Arduino IDE will not download the esp8266 board manager it is giving an error of:-
"Error downloading". Have you got any solutions to my problem. Thanks.

You misspelled the URL. It should end in .json, not _json.

I recommend you take some time to learn how to copy and paste. It's an essential skill for every computer user, and especially for anyone involved in writing code.